Meters are used to measure electricity consumption.
To this end, they include sensor devices that connect to and or interact with the utility power lines (sensor equipment) and electronic circuits for performing various calculations using signals generated by the sensor devices.
Sensor devices typically include blades received by meter socket jaws and provide a mechanically and electrically sound connection for handling large currents and voltages. The blades are often connected within the meter by large current carrying conductors. Sensor devices may also include current measurement devices, which can include a sensing coil of some sort. Voltage and current signals are obtained from these devices and provided to a circuit board that may include a/d converters and processing circuits that perform metering calculations.
One source of cost in the meter is the connection between the sensor devices and the electronic circuitry on the circuit board. Sensor devices are too large to be on circuit board. Typically, sensor devices are mounted to the housing below circuit board and then wire connections are provided to the circuit board. Wires are soldered or connected by terminals.
The manufacturing process of wiring sensor devices to a printed circuit board in a meter has drawbacks, including the labor cost of individually connecting wires, as well as potential quality problems, e.g., difficult to run wires and manipulate them in the small interior.
One alternative is provided by Schlumberger. This meter has preformed mounts for sensors, and leaf spring terminals that extend upward form the sensors to the circuit board. Although this meter alleviates the drawbacks of handwiring, it still has drawbacks.
One problem is that a custom mount must be made for each meter form. In particular, different meters often have different blade and sensor configurations. Specifically, various standardized meter forms have been defined that require different wiring and connections between and among the blade and sensor elements. The different meter forms result from the fact that electrical service is provided in different ways to different customers, and the methods of measuring these different types of services changes.
By way of example, FIGS. 1a, 1b, 1c, 1d, 1e, 1f, 1g and 1h show different sensor wiring configurations for different meter forms. Each of FIGS. 1a-1h shows a representation of a meter base 12 showing the layout of the current blades 14 and a schematic diagram of the connections within the meter base 12, including transformers/coils, potential blades 18 and neutral blades 18a. In addition, many meter forms include switchable potential links 19 as is known in the art.
FIG. 1a shows a form 16/15S four wire wire meter configuration, FIG. 1b shows a form 25S three wire meter configuration, FIG. 1c shows a form 45S three wire configuration, and FIG. 1d shows a 12S three wire configuration. The meter forms illustrated in FIGS. 1a-1d are known as “self-contained” meter forms because the meter blades connect directly to the power lines. By contrast FIGS. 1e-1h illustrated transformer-rated meter forms, which couple to the power lines through a transformer. Specifically, FIG. 1e shows a form 29S four wire configuration, FIG. 1f shows a form 36S four wire configuration, FIG. 1g shows a form 56S three wire configuration, and FIG. 1h shows a form 9/8S four wire configuration. Such meter forms and their configurations as represented in FIGS. 1a-1h are well known in the art.
Because different meter forms require different blade and sensor wiring connections, the use of customized base mounts requires that different base mounts be created for each form, which is not always a cost effective solution because of the tooling costs and logistical costs of manufacturing and maintaining several custom designs.
Accordingly, there is a need for a method of reducing the amount of labor involved in wiring sensor devices of electricity meters to the smaller components on the circuit boards of utility meters that does not require custom molds and manufacturing techniques for each different meter form.